Progressive disruption of the plasma membrane during renal proximal tubulecellular injury

The goal of this study was to examine the progression of plasma membrane di sruption during cell injury using rabbit renal proximal tubules (RPT). The results demonstrated that the plasma membrane became permeable to larger an d larger molecules as anoxia proceeded. At least three distinctive phases o f membrane disruption were differentiated during anoxia. In phases 1, 2, an d 3, plasma membranes became permeable to propidium iodide (PI, molecular w eight = 668), 3 kDa dextrans, and 70 kDa dextrans or lactate dehydrogenase (LDH, molecular weight = 140 kDa), respectively. Phase 1 was reversible by reoxygenation but not prevented by the glycine. Phase 2 was inhibited by gl ycine, Phase 3 was inhibited by several membrane-permeable homobifunctional crosslinkers, dimethyl-pimelimidate (DMP), ethylene-glycolbis(succinimidyl succinate), and dithiobis(succinimidylpropionate), but not by the membrane- impermeable crosslinker dithiobis(sulfosuccinimidylpropionate). In addition , DMP decreased RPT LDH release produced by mitochondrial inhibition (antim ycin A), an oxidant (t-butylhydroperoxide) and a nephrotoxicant that is met abolized to an electrophile (tetrafluoroethyl-L-cysteine). These results id entify (1) different phases of plasma membrane damage with increasing perme ability during cell injury, (2) the reversibility of phase 1, (3) the relat ive site of action of the cytoprotectant glycine (prevents phase 2), and (4 ) the protective effects of chemical crosslinkers in RPT cell death produce d by different toxicants. (C) 2001 Academic Press.